Pictures evoke both a top down and a bottom-up visual percept of balance. Through its effect on eye movements, balance is a bottom-up conveyor of aesthetic feeling. Eye movements are predominantly influenced by the large effects of saliency and top-down priorities; it is difficult to separate out the much smaller effect of balance. Given that balance is associated with a unified and harmonious picture and that there is a pictorial effect known to painters and historically documented that does just that, it was thought that such pictures are perfectly balanced. Computer models of these pictures were created by the author and were found to have bilateral quadrant luminance symmetry with a lower half lighter by a factor of ~1.07 +/- ~0.03. A top weighted center of quadrant luminance calculation is proposed to measure balance. To show that this effect exists, two studies were done that compared identical pictures in two different frames with respect to whether they appeared different given that the sole difference is balance. Results show that with observers, mostly painters, there was a significant correlation between average pair imbalance and observations that two identical pictures appeared different indicating at a minimum that the equation for calculating balance was correct. A conventional study of preference could not be done because of the necessity of using LED pictures that increase overall salience, and so decrease the aesthetic effect while retaining the effects on eye movements. The effect is the result of the absence of balancing forces on eye movements. With painters who can disregard salience, the effect results from the absence of forces drawing attention to any part of the image. All parts of the picture including that in peripheral vision receive attention, and the eye seems to slide through rather than to jump from objet to object. The effect is being called pictorial coherency. Large tonally contrasting forms, geometric forms or many different forms that cannot be visually combined prevent the effect from being seen. Pictorial balance, an unaccustomed visual force, explains why viewing pictures cause fatigue. That pictures can evoke such a low level percept based on luminance would indicate that it belongs to a much earlier evolutionary development of the visual stream where it was possibly used to follow movement by defining a complex object as a simple vector.
Pictorial balance is a bottom-up aesthetic property mediated by eye movements